plugin: Test endpoints via supertest

Unfortunately we can't use node-mocks-http to test a express.Router
that has async routes. See https://github.com/howardabrams/node-mocks-http/issues/225

router will just return undefined if the executing handler is async and
so the test will have no way to wait for it to complete. Thus, we have
to use supertest which starts an actual HTTP server in the background
and uses a HTTP client to send requests.

test/plugin.test.ts

@@ -1,43 +1,57 @@
 import { logger } from "@coder/logger"
-import * as assert from "assert"
 import { describe } from "mocha"
 import * as path from "path"
 import { PluginAPI } from "../src/node/plugin"
+import * as supertest from "supertest"
+import * as express from "express"
+import * as apps from "../src/node/routes/apps"
 
 /**
  * Use $LOG_LEVEL=debug to see debug logs.
  */
 describe("plugin", () => {
-  it("loads", async () => {
-    const papi = new PluginAPI(logger, path.resolve(__dirname, "test-plugin") + ":meow")
+  let papi: PluginAPI
+  let app: express.Application
+  let agent: supertest.SuperAgentTest
+
+  before(async () => {
+    papi = new PluginAPI(logger, path.resolve(__dirname, "test-plugin") + ":meow")
     await papi.loadPlugins()
 
-    const apps = await papi.applications()
+    app = express.default()
+    papi.mount(app)
 
-    assert.deepEqual(
-      [
-        {
-          name: "Test App",
-          version: "4.0.0",
+    app.use("/api/applications", apps.router(papi))
 
-          description: "This app does XYZ.",
-          iconPath: "/test-plugin/test-app/icon.svg",
+    agent = supertest.agent(app)
+  })
+
+  it("/api/applications", async () => {
+    await agent.get("/api/applications").expect(200, [
+      {
+        name: "Test App",
+        version: "4.0.0",
+
+        description: "This app does XYZ.",
+        iconPath: "/test-plugin/test-app/icon.svg",
+        homepageURL: "https://example.com",
+        path: "/test-plugin/test-app",
+
+        plugin: {
+          name: "test-plugin",
+          version: "1.0.0",
+          modulePath: path.join(__dirname, "test-plugin"),
+
+          displayName: "Test Plugin",
+          description: "Plugin used in code-server tests.",
+          routerPath: "/test-plugin",
           homepageURL: "https://example.com",
-          path: "/test-plugin/test-app",
-
-          plugin: {
-            name: "test-plugin",
-            version: "1.0.0",
-            modulePath: path.join(__dirname, "test-plugin"),
-
-            displayName: "Test Plugin",
-            description: "Plugin used in code-server tests.",
-            routerPath: "/test-plugin",
-            homepageURL: "https://example.com",
-          },
         },
-      ],
-      apps,
-    )
+      },
+    ])
+  })
+
+  it("/test-plugin/test-app", async () => {
+    await agent.get("/test-plugin/test-app").expect(200, { date: "2000-02-05T05:00:00.000Z" })
   })
 })

test/test-plugin/src/index.ts

@@ -8,19 +8,24 @@ export const plugin: pluginapi.Plugin = {
   homepageURL: "https://example.com",
   description: "Plugin used in code-server tests.",
 
-  init: (config) => {
+  init(config) {
     config.logger.debug("test-plugin loaded!")
   },
 
-  router: () => {
+  router() {
     const r = express.Router()
+    r.get("/test-app", (req, res) => {
+      res.json({
+        date: new Date("2000/02/05"),
+      })
+    })
     r.get("/goland/icon.svg", (req, res) => {
       res.sendFile(fspath.resolve(__dirname, "../public/icon.svg"))
     })
     return r
   },
 
-  applications: () => {
+  applications() {
     return [
       {
         name: "Test App",